Improvement in hand-pieces for dental engines



`1. w. GILBERT'. Hand-Pieces for Dentu-Engines.

- Patent'ed Dec` 29,1874.V

IN VEA/TOR UNITED STATES PATENT o EE-Ic-E.

'JOHN w. GILBERT, or PHILADELPHIA, PENNSYLVANIA, AsSIeNdt To SAMUEL S. WHITE, oE SAME PLAGE.

IMPROVEMENT IN HAND-PIECES FOR DENTAL ENGINES.

Specification forming part of Letters Patent No. 158,170, dated December 29, 1874; application tiled November 19, 1874..

CASE O.

To all whom t may concern Be it known that I, JOHN W. GILBERT, of the city and county of Philadelphia, in the State of Pennsylvania, have invented a certain new and useful Improvement in Hand- Pieces for Dental Engines, and in tools adapted to be inserted therein, of which the following is a speciiication:

My invention more especially relates to that class of dental drills driven by power, in which the tool is inserted in aholder or chuck rotating in bearings in the hand-piece.

My invention constitutes an improvement on the dental drill for which Letters Patent of the United States (No. 151,614) were granted to William R. Nutz on the Zd day of June, 1874. In the patent aforesaid the tool is shown as constructed with a flattened end, and with an annular groove eccentric to the axis of the tool, by which means the tool could be inserted in the tool-holder or socket, and interlock with thepin intersecting the socket of the toolholder tangentially, so as to hold it in place when in operation.

It is object of my invention to secure a positive lock ot' the tool in the tool-holder; to which end my improvement consists in combining a tubular tool-holder having a lockingpin intersecting the bore thereof tangentially, a wedgeshaped locking-bolt moving endwise in the tool-holder, and the tool having a wedgeshaped transversely-grooved end, whereby it may be inserted into the tool-holder, turned until the tangential pin interlocks with its groove, and then be prevented by the sliding bolt from turning.

In the accompanying drawings, which eX- clnplify the best way now known to me of carrying out the objects of my invention, Figure l represents a longitudinal central section through so much ofthe apparatus as is neces-v sary to illustrate the subject matter herein claimed, showing the tool as locked in its socket. Fig. 2 represents a similar view ot' a portion ofthe instrument with the lockingbolt withdrawn from contact with the end of the tool. Fig. 3 shows the tool in perspective. Fig. 4 represents a vertical transverse section through the instrument on the line x of Fig. l; Fig. 5, a similar section on the line y g/ ot' said Fig. 1. Fig. 6 represents a similar section on the line zz of Fig. l, and Fig. 7 a similar section ou the line w w of Fig. 1.. These four figures last mention ed are on an enlarged scale, and the eyes on Fig. l indicate the direction in which the observer is supposed to be looking.

The hand-piece or casing A is of the usual well-known construction. A pinion wire shaft, B-that is to say, a shaft which in crosssection would look like a toothed gear-wheel driven by power from any suitable motor, ro tates a chuck, socket, or tool-holder, C, rotating in suitable bearings in the casing. This tool-holder is bored out axially from its forward end for a greater portion of its length, for the insertion of the tool, and of a lockingbolt, D, having'a wedge-shaped incline on its forward end. This bolt is movable freely endwise in the socket, and is provided with a coiled spring, a, which tends to keep it' thrust forward. It is also secured by pins to a slide, E, which pins are capable of moving endwise in longitudinal slots in the socket or toolholder.

By this mode of construction the slide acts as a stop to limit the endwise movement ot' the locking-bolt, as a lock to secure its rotation with the tool-holder, and as a latch, by which the locking-bolt may be 'withdrawn from contact with the tool.

In this instance the casing A is shown as provided with a slot directly over the slide E, which opening is covered by a ring or slideplate, F, provided with a lug or thumb-piece, j', by which the slide may be moved upon the casing to retract the locking-bolt; or the same result maybe obtained by leaving off the slideplate and shoving back the slide E by the thumbnail through the opening in the casin g.

A drill, burr, or tool, G, is made with one of its ends wedge shape, and with a transverse groove, g, near the inner end or top of the wedge. A pin, h, is inserted tangentially in the bore of the socket-piece. The tool is inserted into the socket with its inclined face turned toward this pin until the groove g comes opposite the pin. The tool is then turned until the pin locks in the groove, as

shown in Fig. 4. The locking-bolt is then released and thrust forward by a spring into the position shown in Figs. l and 5, When the tool is locked. With equal efficiency against pushing or pulling strains.

As a broad. claim. to a locking-bolt forms the subject-matter of another pending application of mine, I make no claim to this feature herein, except in combination With the peculiar means of fastening the tool, hereinbefore set forth.

- I claim as of my own invention- The combination, substantially as hereinhefore set forth, of the tubular tool-holder, the locking-pin intersecting the bore thereof tangentially, the Wedge-shaped locking-bolt movable endwise in the tool-holder, and the tool having a Wedge-shaped transversely-grooved end interlocking with the pin and lockingbolt, for the purposes specified.

In testimony whereof I have hereunto subscribed my name.

JOHN W. GILBERT.

Witnesses J. A. B. WILLIAMS, J. W. DE BARGER.. 

